1. Field of the Invention
The present invention relates to a desensitizer composition, and more precisely, to a desensitizer composition which reduces the function of a developer to color a substantially colorless color former or causes the developer to lose its ability to cause color formation.
2. Description of the Prior Art
Various methods are known for forming a developed color image utilizing the reaction of a color former, which is a substantially colorless organic compound, and a developer. For example, such a color reaction has been utilized in recording materials as described in U.S. Pat. Nos. 2,505,470; 2,505,489; 2,548,366; and 2,550,471, etc; recording materials as described in U.S. Pat. Nos. 2,712,507; 2,730,456; 2,730,457; and 3,293,060, etc.; recording materials as described in U.S. patent application Ser. No. 40,732, filed May 26, 1970, British Pat. No. 825,354, etc.; and other recording materials for spirit printing, stencil printing, automatic ticket vending systems, fingerprinting systems, letter writing systems, etc.
In these recording materials, the color reaction results from the contact of the color former and the developer, and it is desirable that the color reaction be prevented in the areas which do not need to contain a developed color image, both from the standpoint of the use of these materials and from an economical standpoint. A desensitizer has heretofore been used for this purpose. For example, the following prior art discloses the use of desensitizers: U.S. Pat. No. 2,777,780 (high molecular weight primary alkylamines such as dodecylamine; quaternary ammonium salts such as dodecyltrimethylammonium chloride; alkyl or aryl amine acetates); Japanese Patent Publication No. 29546/71 (tertiary amines derived from a chemical reaction of a monoalkylamine, aralkylamine or ethanolamine and ethylene oxide); Japanese Patent Publication No. 3569/71 (precondensation products of urea resins); etc. (secondary alkylamines such as didodecylamine; tertiary alkylamines such as triethylamine; primary arylamines such as aniline; aralkylamines such as benzylamine; polyhydroxyl compounds such as polyethylene glycol and glycerin).
Some desensitizers do not provide a sufficient desensitization function even if a large amount thereof is used, and other desensitizers do not provide a sufficient desensitization function unless a large amount thereof is used. In particular, these defects tend to be remarkably emphasized to an even greater extent with improvement in color formers and developers.
For example, color formers containing a fluoran nucleus are especially difficult to desensitize, as compared with crystal violet lactone, etc. In addition, these desensitizers are almost ineffective for developers such as phenol resins or metal salts of aromatic carboxylic acid. Therefore, limits on the few advantageous properties of these developers exist, e.g., the developed color image obtained using these developers does not disappear in the presence of water. Another defect of conventional desensitizers is that the non-desensitized areas of a developer gradually color with the lapse of time (that is, fog occurs) when a color former is brought into contact with the desensitized developer using an encapsulation system.
In addition, conventional desensitizers tend to yellow in contact with a developer, or since these desensitizers are used in large quantities, the drying speed is low and it is difficult to increase the coating (printing) speed.